A semiconductor light emitting device, such as a light emitting diode (LED), is a device including a material that emits light through the application of electrical energy thereto, in which energy generated by electron hole recombination in semiconductor junction parts is converted into light to be emitted therefrom. LEDs are commonly employed as light sources in general illumination devices, display devices, and the like, and the development of LEDs has been accelerated.
In particular, recently, the development and employment of light emitting diodes (LEDs) (e.g., gallium nitride-based semiconductor light-emitting devices) has increased, and mobile device keypads, vehicle turn signal lamps, camera flashes, and the like, using such LEDs, have been commercialized, and in line with this, the development of general illumination devices using LEDs has been accelerated. Like the products to which they are applied, such as a vehicle headlight, a backlight unit of a large TV, a vehicle headlamp, a general illumination device, and the like, products in which LEDs are utilized are gradually moving toward large-sized products having high output levels and high efficiency, and thus, the characteristics of LEDs used in such products are required to satisfy the high level characteristics.
As the purpose of light emitting diodes has extended to vehicle headlights, a method for maintaining a uniform quantity of light emitted by LEDs and preventing damage when some of LEDs have an error is required.